<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* .flex {
            display: flex;
            flex-wrap: wrap;
            width: 500px;
            height: 500px;
            background-color: pink;
        }
        .item {
            background-color: #fff;
            width: 33%;
        } */
        .flex {
            width: 500px;
            height: 500px;
            display: grid;
            grid-template-columns: 33% 33% 33%;
            grid-template-rows: 33% 33% 33%;

        }
    </style>
</head>
<body>
    <div class="flex">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
        <div class="item">7</div>
        <div class="item">8</div>
        <div class="item">9</div>
    </div>
</body>
</html>